Compositions and methods for inhibiting protozoan growth

Abstract

The present invention provides compositions and methods for inhibiting protozoan growth comprising a synergistic combination of lipid synthesis inhibitors. In addition, the invention provides compositions and methods that are useful for the treatment of protozoan infections and the identification of potential new drugs for the treatment of protozoan infections.

1 . A composition for inhibiting protozoan growth comprising a first lipid synthesis inhibitor and a second lipid synthesis inhibitor, wherein
 a. the ratio of the EC50 of the first lipid synthesis inhibitor alone to the EC50 of the composition is at least ten, and   b. the ratio of the EC50 of the second lipid synthesis inhibitor alone to the EC50 of the composition is at least ten.   
     
     
         2 . The composition of  claim 1 , wherein
 a. the ratio of the EC50 of the first lipid synthesis inhibitor alone to the EC50 of the composition is at least twenty, and   b. the ratio of the EC50 of the second lipid synthesis inhibitor alone to the EC50 of the composition, is at least twenty.   
     
     
         3 . The composition of  claim 2 , wherein
 a. the ratio of the EC50 of the first lipid synthesis inhibitor alone to the EC50 of the composition is at least fifty, and   b. the ratio of the EC50 of the second lipid synthesis inhibitor alone to the EC50 of the composition, is at least fifty.   
     
     
         4 . The composition of  claim 3 , wherein
 a. the ratio of the EC50 of the first lipid synthesis inhibitor alone to the EC50 of the composition is at least one hundred, and   b. the ratio of the EC50 of the second lipid synthesis inhibitor alone to the EC50 of the composition, is at least one hundred.   
     
     
         5 . The composition of  claim 1 , wherein the first lipid synthesis inhibitor is selected from the group consisting of an ergosterol synthesis inhibitor, a sphingolipid synthesis inhibitor, and an ether phospholipid synthesis inhibitor. 
     
     
         6 . The composition of  claim 5 , wherein the ergosterol synthesis inhibitor is a lanosterol 14α-demethylase inhibitor. 
     
     
         7 . The composition of  claim 6 , wherein the lanosterol 14α-demethylase inhibitor is itraconazole or ketaconazole. 
     
     
         8 . The composition of  claim 5 , wherein the sphingolipid synthesis inhibitor is selected from the group consisting of a serine palmitoyltransferase inhibitor, an inositol phosphorlyceramide synthase inhibitor, and a sphingolipid salvage inhibitor. 
     
     
         9 . The composition of  claim 5 , wherein the first lipid synthesis inhibitor is an ether phospholipid synthesis inhibitor. 
     
     
         10 . The composition of  claim 9 , wherein the ether phospholipid synthesis inhibitor is an alkyl-dihydroxyacetonephosphate transferase inhibitor. 
     
     
         11 . The composition of  claim 5 , wherein the first lipid synthesis inhibitor is a sphingolipid synthesis inhibitor. 
     
     
         12 . The composition of  claim 1 , wherein the second lipid synthesis inhibitor is selected from a different class of lipid synthesis inhibitors than the first lipid synthesis inhibitor. 
     
     
         13 . The composition of  claim 1 , wherein the first lipid synthesis inhibitor is an ergosterol synthesis inhibitor and the second lipid synthesis inhibitor is a sphingolipid synthesis inhibitor. 
     
     
         14 . The composition of  claim 1 , wherein the first lipid synthesis inhibitor is an ergosterol synthesis inhibitor and the second lipid synthesis inhibitor is an ether phospholipid synthesis inhibitor. 
     
     
         15 . The composition of  claim 1 , wherein the first lipid synthesis inhibitor is a sphingolipid synthesis inhibitor and the second lipid synthesis inhibitor is an ether phospholipid synthesis inhibitor. 
     
     
         16 . The composition of  claim 13 , wherein the first lipid synthesis inhibitor is itraconazole or ketaconazole. 
     
     
         17 . The composition of  claim 14 , wherein the first lipid synthesis inhibitor is itraconazole or ketaconazole. 
     
     
         18 . A method for inhibiting protozoan growth, the method comprising contacting the protozoan with an effective amount of a composition comprising a first lipid synthesis inhibitor and a second lipid synthesis inhibitor, wherein
 a. the ratio of the EC50 of the first lipid synthesis inhibitor alone to the EC50 of the composition is at least ten, and   b. the ratio of the EC50 of the second lipid synthesis inhibitor alone to the EC50 of the composition is at least ten.   
     
     
         19 . The method of  claim 18 , wherein
 a. the ratio of the EC50 of the first lipid synthesis inhibitor alone to the EC50 of the composition is at least twenty, and   b. the ratio of the EC50 of the second lipid synthesis inhibitor alone to the EC50 of the composition is at least twenty.   
     
     
         20 . The method of  claim 19 , wherein
 a. the ratio of the EC50 of the first lipid synthesis inhibitor alone to the EC50 of the composition is at least fifty, and   b. the ratio of the EC50 of the second lipid synthesis inhibitor alone to the EC50 of the composition is at least fifty.   
     
     
         21 . The method of  claim 20 , wherein
 a. the ratio of the EC50 of the first lipid synthesis inhibitor alone to the EC50 of the composition is at least one hundred, and   b. the ratio of the EC50 of the second lipid synthesis inhibitor alone to the EC50 of the composition is at least one hundred.   
     
     
         22 . The method of  claim 18 , wherein the protozoan is selected from the group consisting of  Giardia, Trichomonas, Leishmania, Trypansosoma, Entamoeba, Plasmodium, Cryptosporidium, Toxoplasma, Sarcocystis, Theileria, Babesia , and  Eimeria.    
     
     
         23 . The method of  claim 22 , wherein the protozoan is  Leishmania.    
     
     
         24 . The method of  claim 18 , wherein the first lipid synthesis inhibitor is selected from the group consisting of an ergosterol synthesis inhibitor, a sphingolipid synthesis inhibitor, and an ether phospholipid synthesis inhibitor. 
     
     
         25 . The method of  claim 24 , wherein the ergosterol synthesis inhibitor is a lanosterol 14α-demethylase inhibitor. 
     
     
         26 . The method of  claim 25 , wherein the lanosterol 14α-demethylase inhibitor is itraconazole or ketaconazole. 
     
     
         27 . The method of  claim 24 , wherein the sphingolipid synthesis inhibitor is selected from the group consisting of a serine palmitoyltransferase inhibitor, an inositol phosphorlyceramide synthase inhibitor, and a sphingolipid salvage inhibitor. 
     
     
         28 . The method of  claim 24 , wherein the ether phospholipid inhibitor is an alkyl-dihydroxyacetonephosphate transferase inhibitor. 
     
     
         29 . The method of  claim 18 , wherein the second lipid synthesis inhibitor is selected from a different class of lipid synthesis inhibitors than the first lipid synthesis inhibitor. 
     
     
         30 . The method of  claim 29 , wherein the first lipid synthesis inhibitor is an ergosterol synthesis inhibitor and the second lipid synthesis inhibitor is a sphingolipid synthesis inhibitor. 
     
     
         31 . The method of  claim 29 , wherein the first lipid synthesis inhibitor is an ergosterol synthesis inhibitor and the second lipid synthesis inhibitor is an ether phospholipid synthesis inhibitor. 
     
     
         32 . The method of  claim 29 , wherein the first lipid synthesis inhibitor is a sphingolipid synthesis inhibitor and the second lipid synthesis inhibitor is an ether phospholipid synthesis inhibitor. 
     
     
         33 . The method of  claim 30 , wherein the ergosterol synthesis inhibitor is itraconazole or ketaconazole. 
     
     
         34 . The method of  claim 31 , wherein the ergosterol synthesis inhibitor is itraconazole or ketaconazole. 
     
     
         35 . A method for treating infection by a protozoan in a subject comprising administering to the subject an effective amount of a pharmaceutical composition comprising a first lipid synthesis inhibitor and a second lipid synthesis inhibitor, wherein
 a. the ratio of the EC50 of the first lipid synthesis inhibitor alone to the EC50 of the composition is at least ten, and   b. the ratio of the EC50 of the second lipid synthesis inhibitor alone to the EC50 of the composition is at least ten.   
     
     
         36 . The method of  claim 35 , wherein
 a. the ratio of the EC50 of the first lipid synthesis inhibitor alone to the EC50 of the composition is at least twenty, and   b. the ratio of the EC50 of the second lipid synthesis inhibitor alone to the EC50 of the composition is at least twenty.   
     
     
         37 . The method of  claim 36 , wherein
 a. the ratio of the EC50 of the first lipid synthesis inhibitor alone to the EC50 of the composition is at least fifty, and   b. the ratio of the EC50 of the second lipid synthesis inhibitor alone to the EC50 of the composition is at least fifty.   
     
     
         38 . The method of  claim 37 , wherein
 a. the ratio of the EC50 of the first lipid synthesis inhibitor alone to the EC50 of the composition is at least one hundred, and   b. the ratio of the EC50 of the second lipid synthesis inhibitor alone to the EC50 of the composition is at least one hundred.   
     
     
         39 . The method of  claim 35 , wherein the protozoan is selected from the group consisting of  Giardia, Trichomonas, Leishmania, Trypansosoma, Entamoeba, Plasmodium, Cryptosporidium, Toxoplasma, Sarcocystis, Theileria, Babesia , and  Eimeria.    
     
     
         40 . The method of  claim 39 , wherein the protozoan is  Leishmania.    
     
     
         41 . The method of  claim 35 , wherein the first lipid synthesis inhibitor is selected from the group consisting of an ergosterol synthesis inhibitor, a sphingolipid synthesis inhibitor, and an ether phospholipid synthesis inhibitor. 
     
     
         42 . The method of  claim 41 , wherein the ergosterol synthesis inhibitor is a lanosterol 14α-demethylase inhibitor. 
     
     
         43 . The method of  claim 42 , wherein the lanosterol 14α-demethylase inhibitor is itraconazole or ketaconazole. 
     
     
         44 . The method of  claim 41 , wherein the sphingolipid synthesis inhibitor is selected from the group consisting of a serine palmitoyltransferase inhibitor, an inositol phosphorlyceramide synthase inhibitor, and a sphingolipid salvage inhibitor. 
     
     
         45 . The method of  claim 41 , wherein the first lipid synthesis inhibitor is an ether phospholipid synthesis inhibitor. 
     
     
         46 . The method of  claim 45 , wherein the ether phospholipid synthesis inhibitor is an alkyl-dihydroxyacetonephosphate transferase inhibitor. 
     
     
         47 . The method of  claim 35 , wherein the second lipid synthesis inhibitor is selected from a different class of lipid synthesis inhibitors than the first lipid synthesis inhibitor. 
     
     
         48 . The method of  claim 47 , wherein the first lipid synthesis inhibitor is an ergosterol synthesis inhibitor and the second lipid synthesis inhibitor is a sphingolipid synthesis inhibitor. 
     
     
         49 . The method of  claim 47 , wherein the first lipid synthesis inhibitor is an ergosterol synthesis inhibitor and the second lipid synthesis inhibitor is an ether phospholipid synthesis inhibitor. 
     
     
         50 . The method of  claim 47 , wherein the first lipid synthesis inhibitor is a sphingolipid synthesis inhibitor and the second lipid synthesis inhibitor is an ether phospholipid synthesis inhibitor. 
     
     
         51 . The method of  claim 48 , wherein the first lipid synthesis inhibitor is itraconazole or ketaconazole. 
     
     
         52 . The method of  claim 49 , wherein the first lipid synthesis inhibitor is itraconazole or ketaconazole.